Wing construction



Sept. 17, 1935. R. R. osBoRN 2,014,776

WING CONSTRUCTION Filed Feb. 1, 193s 2 sheets-sheet 1 INVENTOR ROBERT l2, OsBoRN.

||||II||| IIIINN BY HLS ATTORNEY Sept. 17, 1935. R. Rl osBoRN WING CONSTRUCTIGN Filed Feb. l, 1933 2 Sheets-Sheet 2 FIGTZ -l/ xi..

` lNvEN'roR ROBERT E. osoRN.

BY l-ns ATTORNEY Patented Sept. 17,

WING CONSTRUCTION nahm a. ogm, Kenmore, N. r., assignmto Curtiss Aeroplane llilkotor Company, Inc., a

notation o( New Yo Application February 1, 1933, Serial No. 654,641

l (Elim. (Cl: 244-31) n This invention relates to aircraft, and more ltiligticiii'iarly to access openings in the wings reo An object of the invention is to provide al struc- 5 tureforalargeaccessopeninginthewingofanaircraft.

Another object is to provide a partial truss structure for the wing of an aircraft and a cover for an access opening, which is adapted to complete the partial truss structure.

A further object is to provide a metallic access opening cover which carries structural members adapted to form part of the wing structure.

A further object is to provide an unusually large access opening in a. wing to allow greater accessibility to the interior parts thereof than has heretofore been possible.

Another object is to provide an access opening in a wing large enough to allow of the installation, removal, and-servicing of control mechanism located within the wing.

A still further object is to provide a novel wing structure and means for removably fastening part of said structure to the balance of said structure.

Further objects will be apparent from a reading of the subjoined specification and claim, and E? a consideration of the accompanying draw- .35 covering is adequate for aircraft of moderate speeds, but greater serviceabillty and strength result from the more solid coverings. In wings', as has been the practice Vin the past, it is customary to install control members for the opera- Y tion of ailerons, flaps, auxiliary airfoils and the Fig It is, of course, to provide for like.

inspection of such control-mechanism and to provide for the inspection of the internal structure of the wing, such as struts, ribs and the like. so

46 that safe illght conditions may at all t maintained. Y

In the past, small inspection openings have frequentiy been provided so that access may be obtained to movable joints and memberswithin the but such openings are usuallyinadequate Recenuy it has been mund desu-atie to provide to conserve weight and to make the cover more rigid and stronger, I provide ribs or stiifening members on the inner side of the access cover which are adapted to cooperate with and to form a part of the structure of the airfoil itself. In 5 the embodiment shown, I provide a large access opening in the under side of the conventional wing which has the usual spars and truss ribs. A portion of the lower chord member of those ribs included in the area bounded by the access o'pen- 10.

ing, is attached rigidly to the access covering.- and when the cover is installed, these stiffeners cooperatewith the rib trusses to form part of the lower chord members thereof.

It is to be noted that the covering of the wing, 15

in itself, and also the access cover. are arranged to assume certain stresses such as, but not limited to, drag and anti-dragstresses. It is well known that the covering skins of airfoils have been used for assuming drag and anti-drag stresses, but it 20 is believed novel to combine an accessy cover which,

Vwith the balance of the wing covering, will assume these stresses. .In the past. it has been the custom to reinforce the edges of the covering skin opening, to assume the loads which would other- 25 reference may be made to the drawings, in which: 30

A Fig. 1l is a bottom view of .an aircraft wing aonstructed in accordance with my invention, with a fragmentary portion of the access cover attached` thereto;

Fig. 2 is a partial section on the line 2-2 of 3.5.

Fix. 1; a

Fig 3isapartialsectiononthe line I-Iof Fig. 1;

Fig. 4 isla partial section on the line I-I of '40 1, Fig. 5 isa partial section onthe line 5-5 of Fig. 1; Y

Fig. 6 is a perspective view of one of the fittings' shown also in Fis- 2;

Fig. 7 isan. enlarged section of the rearward 45 'portion of the'wlnginFig. 1;

Fig. 8 is abottom view of avportion of the wing; and

Fig. 9 is a perspectlve view of a portion of the accesscovershownalsoinFigs..'Iand8. 50

Referring to Fig. 1, a wing II is provided with a rear spar I2 and a front spar I3 extending along the span of the wing. Rearward of the spar lzmaybeprovidedanaileron Manda mixing edge nap 11m-ward orme spar n, 55

an auxiliary airfoil, whereby a leading 'edge slot,` may be formed. 'I'he wing II is provided with a covering I1, and in the covering I1, between the spars I2 and I3, an opening I8 is formed. V A plurality of ribs I9 and I9 are adapted to bridge the gap between the front spar I3 and the rear, spar I2, such ribs serving to distribute air loads imposed on the covering I1 to the spars I2 and I3. The ribs I9 are conventional, and lie outside of the area enclosed by the access open- The ribs I8 which bridge the spars in the neighborhood of the access opening I8, comprise an upper chord member 28 extending from the upper surface of the spar I3 to the upper surface of the spar I2. Truss members 2|, 22, 23, 24 and 25 are attached to the chord member 28 and serve, as will be later described, to form part of the complete rib I9. In the embodiment shown, the truss member 2| extends diagonally from the lower surface of the spar I3 to the chord member 20. The truss members 22, 23 and 24 are attached to the chord memberv 20 at their upper ends, and are attached to each other by means of a tting 26 at their lower ends. The truss member 25 extends diagonally from the vupper chord member 20 to the lower surface of the rear spar I2. The fitting 26, shown in perspective in Fig. 6, comprises a gusset portion 21 provided with holes 28 to which the truss members 22, 23 and 24 may be attached as by riveting, and a ange portion 29 bent at substantially a right angle to the gusset portion 21. The flange 29 is provided with a threaded bushing 30 to which the access covering later to be described, may be attached.

Referring now to Fig. 7, the lower surface of each spar I2 is provided with a iiangev3l which notv only serves as a reinforcing chord member for the spar I2 but, by being provided with a.

threaded bushing 32 at its forward edge, serves to provide holding means for an access co'ver 33.-

The lower rearward edge of the forward spar I3 is provided with a flange identical in its character with the fiange 3I. Such a flange on the lower surface of the spar I3 is also provided with a threaded bushing similar to 32.

'Ihe access cover 33 comprises a substantially fiat plate ot metal or other'suitable material adapted to completely cover the access opening I8. At its edges, as shown in Figs. 7, 8 and 9, it is provided with a reinforcing strip 34 riveted thereto as by rivets 3l. The strip 34 is provided with a plurality of openings 36 spaced to register with the threaded openings in the bushings 32 which are attached, as previously indicated, along the Ainner edges of the flange 3l, and of a similar loads which may be imposed thereon. Drag or anti-drag stresses assumed by the covering I1, may be transmitted directly through the cover 3 3, the usual bulky frame for an access cover being thus eliminated, saving weight and complexity. The attachment of the cover 33 to the lope for the wing. By the use of flat metal sheet in the covering l1 and the cover 33, all drag and anti-drag stresses may be assumed therein, eliminating the usual interior diagonal wire or strut drag and anti-drag bracing necessary in wings 5 the lower. chord member of such rib. By the attachment of the brace 38 tothe strip 34, and of the attachment of the strip 34 to the flange 3|, a rigid joint is .effected whereby the truss stresses may be properly distributed among the. 20 rib members 20, 2l, 22, 23, 24, 25 and the brace 38. To further complete the rib truss structure, the mid portion of the brace 38, between the spars I2 and I3 is adapted to be attached to the fittings .26 of each rib. An opening is formed 25 through the cover 33 andthe brace 38 to register' with the threaded bushing 30 carried by the f1tvting 26, and a screw-42 may then be inserted from the outside of the wing and screwed into the bushing 30, thus holding the cover 33 and the 30 In the normal wing, a plurality of compression members, such as 43 and 44, are spaced laterally between the wing spars. In the embodimentshown, compression ribs 43 form the lateral edges of the access opening I8, 'to which the 45 lateral edges of the cover 33 are attached.v Attaching means are provided as shown in Fig. 3.

A lower channel-shaped chord member 45 for the compression rib 43, is provided von its inner face with a plurality of spaced threaded 50 bushings 4B. The lateral edge of the cover 33 has attached thereto a reinforcing strip 41, having openings 48 for registrywith the openings in the threaded bushings 46. Screws 49 may then be linserted through the openings 48 to engage 55 the bushings 46 to hold the lateral edges of the cover 33 firmly to the wing. It may be noted that the permanent covering I1 is also attached to the compression ribs 43, as by rivets 58, so that the covering I1 and the access cover 33, 60 when assembled, lie flush and present a smooth surfacefor air flow thereover.

In a large access cover, such as that shown. it may be considered desirable to make it in several sections, to make handling, attachment and removal an easierl service operation. This is accomplished by providing a sectional cover adapted to extend transversely from one compression rib, such as 43, to the next compression rib 44, another sectional4 cover such as 33 extend- 'I0 ing from the compression rib 44 to the compression rib 44', and still another sectional cover, such as 33", extending from the compression rib 44 to the compression rib 43. Attachment of covering I1, gives, in effect, a continuous envethe sectional covers 33' and 33" is eifected in a 1I manner similar to that provided for the extreme lateral edges of the cover 33, described above.

For instance, the intermediate compression ribs such as 44 and 44 are provided with a plurality of threaded bushings 46', arranged in a line along the inner surface of the rib chord member 45' (shown in Fig. 4). Into these bushings, screws 49 are driven from the outside to hold the border strip 41' forming part of the cover section 33'.t Similarly, the cover section '33" is provided with a border strip 41", which is held adjacent the rib chord member 45' -by screws' 49" driven into a plurality of threaded bushings 46", arrangedv in a line parallel tothe Y line of the bushings 46.

" relationship with the will be obvious to those skilled in the art, after understanding my invention, that various changes and modifications may be made therein without departing from the spirit or scope thereof. I

aim in the appended claim to cover all such modications and changes.

What is claimed is:

In anaircraft wing comprising forwardiand rearward spars joined by spaced compression members, a plurality of ribs parallel to and more narrowly spaced than said members, also joining said spars, said ribs comprising trussed chord and bracing elements,- one said chord element of each rib being separate from the balance of said rib, a metallic sheet fixed to the several said detachable rib chord elements, said sheet being bounded at its forward and rearward edges by said forward and rearward spars respectively, and being bounded at each lateral edge thereof by one said compression member, and means for removably attaching the several sheet edges at frequently spaced intervals to the forward and rearward spars and compression members,

ksaid sheet, when attached, holding said detachable r-ib chord elements in the proper cooperative respective ribs. ROBERT R. OSBORN. 

